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Biomedical subjects

R Ito

Publications and source records attributed to R Ito.

At least 19 recordsLinked to original sources

Novel muteins of human tumor necrosis factor alpha.

For chemical synthesis of a gene coding for human tumor necrosis factor alpha (TNF-alpha), DNA sequence predicted by the amino acid sequence of human TNF molecule was prepared. Codons were chosen according to the codon usage in Escherichia coli (E. coli). The 490 bp gene was assembled by enzymic ligation of 42 oligonucleotides and was cloned into a vector (pKK223-3) for high expression of active TNF-alpha in E. coli. With use of site-directed mutagenesis on this DNA, five different muteins of TNF-alpha were synthesized. TNF-M1 and TNF-M4 have deletions of His-73 and Gln-102, respectively. These deletions didn't cause loss of the cytotoxic activity against L929 cells. TNF-M5, which has a substitution of Asp-10 to Arg, had the similar cytotoxic activity to that of TNF-alpha. The cytotoxic spectra against several tumor cells were not changed by this substitution. TNF-M3 has an amino acid substitution of Glu-116 to His which occupies this position in human TNF-beta. This substitution didn't change the cytotoxicity. In addition, evidence was presented that the change of the carboxyl terminal residue doesn't always influence the cytotoxic activity of TNF-alpha. Many different muteins were also isolated by random mutagenesis with hydroxylamine-HCl. One of the muteins, which carries a mutation of His-15 to Tyr, lost the cytotoxic activity almost completely.

Amino Acid Sequence

Immunohistochemical study of tyrosine-hydroxylase-positive cells and fibers in the chicken spinal cord.

Tyrosine hydroxylase (TH)-positive cells and fibers were examined by immunohistochemistry in the chick spinal cord. TH-positive cells, which were located in laminae I, V and X, were most frequently found in the rostral part of the cervical spinal cord, with fewer cells being found in more caudal levels of the spinal cord. TH-positive cells located in lamina X, which were bipolar in shape, were mainly found in regions lateral as well as just ventral to the central canal. They had processes reaching to the central canal. The terminals of these cerebrospinal-fluid-contacting cells were oval in shape, and were most frequently found at the ventral wall of the central canal. There were dense clusters of TH-positive fibers in lamina X. A meshwork-like structure of TH-positive fibers was found over the lateral wall of the central canal. A high density of TH-positive fibers was also found in the medial part of laminae V-VII. In lamina IX, small numbers of TH-positive fibers were observed in the lateral motor column of the brachial spinal cord, and in the medial and lateral motor columns of the lumbosacral spinal cord. However, within the medial motor column of the brachial spinal cord TH-positive fibers were densely distributed around somal as well as dendritic profiles. Similar to our previous observations on serotoninergic fibers. TH-positive fibers were also differentially distributed in the ventral horn of the chicken spinal cord: a high density of TH-positive fibers was localized to specific regions of the spinal motor nucleus.

Animals

Electron microscopic studies on the in vitro proliferation of spotted fever group rickettsia isolated in Japan.

Rickettsia was isolated from a patient with Japanese spotted fever, and its proliferation in cultured green monkey kidney cells was observed by electron microscopy. In the course of this study, we observed fusion of infected cells to uninfected cells which may be a way of spreading the rickettsiae from a cell to another. On the other hand, whirlpool-like, multilayer membranous structures, similar to the mesosomes of gram-negative bacteria, were sometimes seen in the rickettsial cells. The other profiles common to the other rickettsiae in spotted fever group were observed, such as the electron-lucent halo zone around the rickettsiae, and external fibrous materials on their surface, but intranuclear multiplication was rarely observed.

Cell Division

Immunity to measles in a large population of varying age. Significance with respect to vaccination.

During a measles outbreak, 660 hospital employees of widely varying ages were screened for immunity to the disease using an automated indirect fluorescent antibody technique. Of these 660 employees, 623 indicated their year of birth; 21 were seronegative and 13 had borderline titers. Of those born before 1957, 7 tested seronegative and 6 were borderline, while 12 of those born between 1959 and 1964 were seronegative and 3 were borderline. There are several possible reasons for these findings. It is concluded that mass immunization of high-risk populations during outbreaks, while effective, is difficult to justify scientifically because only a small percentage of subjects are not immune. If facilities permit, mass screening during outbreaks may be feasible. Preferably, continuous screening and vaccination of susceptible high-risk employees could be performed. Our study also does not validate exclusion from immunization programs those born prior to 1957 in view of the fact that both seronegativity and disease occur in this age group with significant frequency.

Adult

Descending projections from the hypothalamic paraventricular nucleus to the A5 area, including the superior salivatory nucleus, in the rat.

The descending projection of the hypothalamic paraventricular nucleus (PVN) to the A5 area was elucidated using a technique that combines retrograde labeling with horseradish peroxidase (HRP), anterograde labeling with PHA-L (Phaseolus vulgaris leucoagglutinin and immunohistochemistry for dopamine-beta-hydroxylase (DBH). Following an iontophoretic injection of PHA-L into the PVN, HRP was applied to the greater petrosal nerve. Frozen sections of the hypothalamus and the caudal pons were first treated according to a protocol for HRP histochemistry using tetramethylbenzidine with cobalt-enhanced diaminobenzidine, and then they were processed for displaying PHA-L, and then for DBH immunohistochemistry. PHA-L labeled fibers from the PVN were observed in a ventrolateral part of the pontine reticular formation corresponding to the A5 area, where they give rise to a dense network around the cells of origin of the greater petrosal nerve (GPN cells) and DBH-positive cells. Terminals or varicosities labeled with PHA-L were preferentially observed around the somata of GPN cells, suggesting direct contact. However, apparent contact between both elements was hardly ever observed. On the other hand, terminals or varicosities were occasionally observed in close relation to DBH-positive cells. These results suggest that descending fibers of the PVN project more strongly to GPN cells than to DBH-positive cells. The relationship of this fiber pathway to control of the secretomotor or cardiovascular systems is discussed.

Animals

[A case of recurrent ovarian cancer markedly responding to daily oral administration of low dose etoposide].

A 67-year-old woman with recurrent ovarian cancer, who had carcinomatous peritonitis and large abdominal cystic lesions, was treated by daily oral etoposide at a dose of 50 mg/day for 21 consecutive days at 2-week intervals in the outpatient department. After 15 days of administration, the serum level of CA125 decreased from 2,220U/ml to 445U/ml, and that of LDH from 2,725 WU to 906 WU. After the third course of treatment, the abdominal cystic lesions were remarkably reduced, and the performance status improved grade 1 from 3 prior to the administration. No severe side effects except for alopecia and mild myelosuppression were noted during the 3-month treatment.

Administration, Oral

Direct projection from the dorsal hypothalamic area to the nucleus raphe pallidus: a study using anterograde transport with Phaseolus vulgaris leucoagglutinin in the rat.

A hypothalamic projection to the nucleus raphe pallidus of the medulla was examined using the anterograde tracing technique based on Phaseolus vulgaris leucoagglutinin (PHA-L) in the rat. After the iontophoretic application of PHA-L to the dorsal hypothalamic area, labeled fibers that finally ended in the nucleus raphe pallidus were observed descending through the most medial part of the ventral tegmental area and the nucleus reticularis tegmenti pointis to reach the medial aspect of the pyramid. Many varicose fibers forming a loose plexus were observed in the nucleus raphe pallidus, especially ventrally. The ventral surface of the pyramid and the most ventral region of the nucleus reticularis paragigantocellularis lateralis (PGCL) contained labeled varicose fibers. At the electron microscopic level, the labeled profiles in the nucleus raphe pallidus were small-sized unmyelinated axons and axon terminals. Labeled axon terminals containing spherical synaptic vesicles formed synapses on spine-like protrusions or small-sized dendritic shafts. These results strongly indicate that neurons in the dorsal hypothalamic area have a direct connection with neurons in the nucleus raphe pallidus and the ventral part of the PGCL. The possible involvement of this pathway in cardiovascular regulation was discussed.

Animals

[In vitro susceptibility of a strain of Rickettsia recently isolated from a case of Japanese spotted fever to chemotherapeutic agents].

The in vitro susceptibilities to five chemotherapeutic agents against a rickettsial strain which was isolated from a case of Japanese spotted fever were determined by cell culture system. Minocycline was the most effective (MIC, 0.15 micrograms/ml) followed by Tetracycline and Demethylchlor tetracycline (0.31 micrograms/ml 0.16 micrograms/ml). Chloramphenicol was less effective (5 micrograms/ml) and Aminobenzyl-penicillin was not effective with the MIC of 10 micrograms/ml or less. Thus, the earlier administration of Minocycline is recommended to clinically suspicious cases of Japanese spotted fever as well as Tsutsugamushi disease.

Anti-Bacterial Agents

[Study of reinduction chemotherapy in bone marrow relapse of childhood acute lymphoblastic leukemia].

Twenty children with acute lymphoblastic leukemia (ALL) in relapse were treated with various combinations of anti-leukemic agents in approach to the induction of remission. Among them, the four-drug reinduction regimen consisting of prednisolone, vincristine, daunomycin and L-asparaginase (PVDA regimen) was found to be highly effective. The incidence of remission was 100% (2/2) for first reinduction. The regimen also proved to be effective in the management of multiple subsequent relapses. The rate of remission induction for second and third to fifth reinduction attempts were 60% (3/5) and 50% (4/8), respectively. The over all remission rate was 60%. The median duration of subsequent remission for the entire patients treated by PVDA regimen was short, only 11 weeks (range: 3 to 26 weeks). PVDA regimen was effective in reinduction of remission in childhood ALL with relapse, but was not effective in remission maintenance. Optimal maintenance therapy for subsequent remissions has to be determined.

Adolescent

[Severe aplastic anemia successfully treated with cyclosporin A and prednisolone].

A 7-year-old boy was admitted to our department complaining pale face and subcutaneous bleeding in August, 1987. Peripheral blood analysis showed pancytopenia of WBC 2,600/microliter, RBC 148 x 10(4)/microliter and platelets 5,000/microliter. Bone marrow biopsy revealed hypocellularity. Granulocytes 104/microliter, reticulocytes 4,290/microliter and platelets 5,000/microliter were compatible with the diagnosis of severe aplastic anemia based on the criteria of the Ministry of Public Welfare in Japan. Prednisolone (PDN) was initially indicated and bolus methylprednisolone, metenolone and ALG therapy followed with no hematological improvement. Fifteen months after admission, in addition to 0.5-1 mg/kg/day of metenolone, Cyclosporin A (CyA) was started at a dose of 12 mg/kg/day for a week and 6 mg/kg/day thereafter. After a week from administration of CyA, 1 mg/kg/day of PDN was given because his bleeding tendency became worse. But this combination was complicated with liver damage and hyperglycemia to discontinue both drugs. These adverse effects were subsided within 7 days by cessation of the drugs. CyA was started again at a dose of 6 mg/kg/day without any response for 4 weeks. Then PDN was added together at a reduced dose of 0.5-1 mg/kg/day. Hematological response was obtained promptly. Granulocytes reached 1,500/microliter, hemoglobin 10.2 g/dl and platelets 26,000/microliter after 3 months of therapy. Afterward the patient became transfusion independent. The most effective method of CyA administration for aplastic anemia is still controversial. Alternative use of CyA, considering combination of steroids or anabolic steroids, in patients who failed to respond to conventional immunosuppressive treatments should be further investigated.

Anemia, Aplastic

Ultrastructural features of functionally identified primary afferent neurons with C (unmyelinated) fibers of the guinea pig: classification of dorsal root ganglion cell type with reference to sensory modality.

Intracellular labeling of neurons permitted a direct correlation of neuronal profiles with sensory modality of cutaneous receptors. In the guinea pig, 47 neurons in the dorsal root ganglion (displaying C-fiber conduction velocities) were labeled with horseradish peroxidase (HRP) by iontophoresis after determining the sensory modality. Receptive field were explored with systematic "natural" stimuli. Cell areas of all C-fiber units were measured by tracing the cellular contour in light microscopy. The mean cellular diameter calculated from cell areas was 21.8 microns in the second cervical ganglion of the guinea pig. Mean cell diameter for high-threshold mechanoreceptors was 20.9 microns, 24.6 microns for polymodal nociceptors, and 25.7 microns for mechanical-cold nociceptors. Electron microscopic observations showed that all labeled neurons of C-fiber units had profiles of small, dark type-B neurons. Neurons representative of each sensory modality exhibited different cell features, each belonging to a distinct subtype of small B neurons. High-threshold mechanoreceptor and mechanical-cold nociceptor displayed a peripheral lamellar arrangement of cisternae of endoplasmic reticulum (ER), corresponding to the B1 subtype. Polymodal nociceptor units were characteristically of the B2 subtype, in which stacks of long and short cisternae of ER were distributed randomly throughout the cytoplasm, and the arrangement of Golgi bodies varied among these cells. Cooling receptors displayed poorly developed, flattened cisternae of ER and numerous vesicles, typical of the B3 subtype. These results imply that all C-fiber cells belong to the small B-type cell category and that the ultrastructural features of the neuron in the dorsal root ganglion may reflect the sensory modality of the receptive field.

Animals

Ultrastructural study on the meninx of the goldfish brain.

The cranial meninges of the goldfish were studied by means of transmission electron microscopy combined with the freeze-fracturing technique. The goldfish has three cranial meninges. The outer layer consists of flattened cells, which are stratified in 3 to 7 layers and are packed densely with many interdigitations of cell processes. The constituent cells in the outer layer have copious smooth endoplasmic reticulum and are joined by gap junctions but have no desmosomes. The intermediate layer is thin, continuous, and single cell. In the replicas, both the upper and the lower surfaces of the intermediate layer cells have numerous openings of pinocytotic vesicles, but the upper surface is characterized by round gap junctions, whereas the lower surface is identified by a linear continuation of a combination of tight junctions and gap junctions and by desmosomes. The lateral surface has a hexagonal network of tight junctions and gap junctions with internally located desmosomes, which functions as a barrier to intercellular movement of lanthanum. The inner layer consists of a meshwork of reticular cells and large intercellular spaces, in which fine granular material, capillaries, and different types of blood-derived free cells can be found. Cells in the inner layer contain rough endoplasmic reticulum stacked in lamellae and have irregular processes joined by desmosomes. The goldfish meninges are compared with the meninges of mammals.

Animals

Mechanism of transcription termination in eukaryotic cell.

We developed an in vivo screening system for the DNA region involved in transcription termination. This system is based on the idea that the CAT gene bearing transcription terminator upstream of poly(A) signal should produce a low CAT activity in the transfected cell. Using this system, we located termination elements in the human gastrin gene and adenovirus E1 gene. Furthermore, the terminator of gastrin gene was identified by S1 nuclease mapping and in vitro transcription.

Adenovirus Early Proteins

The topographical organization of neurons in the dorsal hypothalamic area that project to the spinal cord or to the nucleus raphé pallidus in the rat.

The present study was undertaken using retrograde labeling techniques to clarify whether the neurons in the dorsal hypothalamic area (DHA) that project to the spinal cord are the same as those that project to the nucleus raphé pallidus (NRP). Following an injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) in the NRP many labeled small neurons (6-13 X 9-22 microns) with an oval shape were found in the ventromedial part of the DHA. At the level of the dorsomedial hypothalamic nucleus, they formed a distinct and compact cell cluster. Labeled neurons, which were large in size (9-22 X 11-36 microns) with oval and triangular shapes, were found mainly in the dorsolateral part of the DHA after injections of horseradish peroxidase (HRP) in the spinal cord. In a double-labeling experiment, Fast Blue or True Blue, and Nuclear Yellow were injected in the NRP and in the spinal cord, respectively. A large number of blue-fluorescent neurons were located mostly in the ventromedial part of the DHA, while yellow-fluorescent ones were found in the dorsolateral part of the DHA. However, no double-labeled neurons were found in the DHA. These results show that the neurons of the DHA projecting to the NRP are essentially different from those which project to the spinal cord.

Animals

The terminal distribution pattern of spinocerebellar fibers. An anterograde labelling study in the posthatching chick.

The terminal fields of spinocerebellar fibers from different levels (cervical, thoracic and lumbar) of the spinal cord in the chick were determined by using wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP), an anterograde labelling technique. More terminals were found in the anterior lobe than in the posterior lobe. Following injections in the lumbar spinal cord, mossy fiber terminals were found mostly in the anterior lobe (lobules I-V). The highest density of labelled terminals was found in lobule I, and labelled terminals were found in all parts of the lobule. However in lobules II-IV, labelled fibers were mediolaterally arranged in three longitudinal strips on both sides of the midline, and formed a distinct zonal distribution pattern. Labelled terminals were distributed evenly from the apical to basal regions of lobules I-V. A large number of mossy fiber terminals originating from the thoracic spinal cord were located in the anterior lobe and lobule VI; some labelled terminals were found in lobule IX. Three less distinct longitudinal strips, compared to those following WGA-HRP injections in the lumbar spinal cord, were recognized on each side of the midline. Labelled mossy terminals were observed in lobules II-IX following WGA-HRP injections in the cervical spinal cord. In transverse sections two longitudinal strips were found at the apical parts of lobules II and III, whereas four thin longitudinal strips were located in lobules IV and V. The present study showed that the terminal fields of spinocerebellar fibers from each level of the spinal cord have different distribution patterns.

Afferent Pathways

Gallium-67 myocardial imaging for the detection of myocarditis in the acute phase of Kawasaki disease (mucocutaneous lymph node syndrome): the usefulness of single photon emission computed tomography.

Myocardial imaging with gallium-67 citrate was used to detect myocarditis in 46 consecutive infants and children (31 boys and 15 girls, mean age 21 months) with Kawasaki disease. In all of them planar imaging (group A) was performed at 6 hours and at 48 or 72 hours after the intravenous administration of a mean (SD) dose of gallium-67 citrate (0.07 (0.02) mCi/kg). Thirty four patients (24 boys and 10 girls, mean age 21 months) also had single photon emission computed tomography imaging (group B) soon after planar imaging. The patients had been ill for from 5 days to 16 days (mean (SD) 10.5 (2.4) days in group A and 10.6 (3.0) days in group B). The colour images obtained at 48 or 72 hours were positive in 41% of group A and in 64% of group B. Among the patients with clinically suspected myocarditis, 63% in group A and 80% in group B had positive myocardial images. Single photon emission computed tomography imaging permitted the identification of tracer in the myocardium, the pericardium only, or in the heart chambers. Myocardial imaging with gallium-67 citrate, especially when used with single photon emission computed tomography imaging, is useful for the detection of myocarditis in the acute phase of Kawasaki disease.

Acute Disease